This application is a division of application Ser. No. 518,556, filed July 29, 1983, now U.S. Pat. No. 4,518,434.
In one aspect, the invention relates to a novel carbon black. In another aspect, the invention relates to a process for preparing a novel carbon black. In another aspect, the invention relates to a novel rubber composition containing carbon black.
It is well known that the pH of a carbon black has a marked effect on the rate of vulcanization of the rubber into which it has been compounded. High pH carbon blacks accelerate cure or vulcanization. A problem with very rapid cure rates in rubber compounds is that it is difficult to control the properties of the finished rubber product. Control of tensile strength, heat buildup, compression set, hardness, resistance to abrasion, modulus of elasticity, elongation, and the like is complicated by fast cure.
Carbon blacks having a low pH impart a reduced "scorchiness" and slower rate of curing of the rubber into which they have been compounded. This enables closer control of the properties in the final rubber product, such as by manipulating the amounts of organic accelerator and sulfur in the masterbatch.